TinyURL

I recently came across this Question on stack overflow about someone wanting to write a URL shortener service like TinyURL.

http://stackoverflow.com/questions/742013/how-to-code-a-url-shortener

Upon further reading, it occurs to me that TinyURL probably use some similar table look-up implementation.  I.e. 

1. "http://tinyurl.com/dbeeod" where "dbeeod" is the key and the looked up value is "http://www.infoq.com/presentations/Making-Roles-Explicit-Udi-Dahan"
   
2. Then TinyURL simply does a redirect from the key to the looked up URL. 
   

Seems like a logical way to implement the solution for this problem.  

I have been using TinyURL for links on my tweets on Twitter, then it dawns on me, if TinyURL goes down or goes out of service, all the TinyURL links will be brokens.